Process for the preparation of spherically shaped microcomposites

ABSTRACT

A process for the preparation of at least one spherically shaped porous microcomposite is provided which microcomposite comprises a perfluorinated ion-exchange polymer containing pendant sulfonic and/or carboxylic acid groups entrapped within and highly dispersed throughout a network of inorganic oxide, wherein the weight percentage of the perfluorinated ion-exchange polymer in the microcomposite is from about 0.1 to about 90 percent, and wherein the size of the pores in the microcomposite is about 0.5 nm to about 75 nm; said process comprising the steps of: (a) combining a water-miscible inorganic oxide network precursor system, a water-miscible liquid composition comprising a perfluorinated ion-exchange polymer containing pendant sulfonic and/or carboxylic acid groups, and an organic liquid to form a two phase liquid system; (b) agitating the two phase liquid system sufficiently to sustain a dispersion of the water-miscible phase in the shape of spheres in the organic phase; (c) allowing the inorganic oxide network precursor system to form a network of inorganic oxide to yield at least one spherically shaped porous microcomposite having the above-described properties; and (d) recovering the at least one spherically shaped porous microcomposite.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/588,528,filed Jun. 6, 2000, now U.S. Pat. No. 6,262,326, which is a divisionalof application Ser. No. 09/155,261, filed Sep. 24, 1998, now U.S. Pat.No. 6,107,233, which was filed under 35 U.S.C. 371 from InternationalApplication No. PCT/US97/04704, filed Mar. 24, 1997, which is acontinuation from U.S. application Ser. No. 08/623,272, filed on Mar.28, 1996, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to a process for preparing a sphericallyshaped microcomposite comprising a perfluorinated ion-exchange polymercontaining pendant sulfonic acid groups and/or pendant carboxylic acidgroups entrapped within and highly dispersed throughout an inorganicoxide network. Due to their high surface area and acid functionality,these spherically shaped microcomposites possess wide utility asimproved solid acid catalysts.

A microcomposite comprising perfluorinated ion-exchange polymerscontaining pendant sulfonic acid groups and/or pendant carboxylic acidgroups entrapped within and highly dispersed throughout a metal oxidenetwork and its preparation are disclosed in WO95/19222. Themicrocomposites described therein are irregular shaped particles whichcan be subject to attrition. Attrition can lead to fines which can causeproblems in certain filtering processes and columns, such as clogging,pressure build up and the generation of friction. Fines can also findtheir way into a final product in certain applications which isundesirable.

Canadian Patent Application No. 2,103,653 describes shapedorganosiloxane polycondensates in the form of macroscopic sphericalparticles. The polycondensates described contain no perfluorinated ionexchange polymer.

It is an object of the present invention to provide a shapedmicrocomposite that possesses high catalytic activity, high attritionresistance, and better handling characteristics.

SUMMARY OF THE INVENTION

The present invention provides a process for the preparation of at leastone spherically shaped porous microcomposite which comprises aperfluorinated ion-exchange polymer containing pendant sulfonic and/orcarboxylic acid groups entrapped within and highly dispersed throughouta network of inorganic oxide, wherein the weight percentage of theperfluorinated ion-exchange polymer in the microcomposite is from about0.1 to about 90 percent, and wherein the size of the pores in themicrocomposite is about 0.5 nm to about 75 nm; said process comprisingthe steps of:

(a) combining a water-miscible inorganic oxide network precursor system,a water-miscible liquid composition comprising a perfluorinatedion-exchange polymer containing pendant sulfonic and/or carboxylic acidgroups, and an organic liquid to form a two phase liquid system;

(b) agitating the two phase liquid system sufficiently to sustain adispersion of the water-miscible phase in the shape of spheres in theorganic phase;

(c) allowing the inorganic oxide network precursor system to form anetwork of inorganic oxide to yield at least one spherically shapedporous microcomposite having the above-described properties; and

(d) recovering the at least one spherically shaped porousmicrocomposite.

DETAILED DESCRIPTION

This invention is directed to a process for preparing at least onespherically shaped porous microcomposite having a diameter of about 0.1to about 1.0 mm, a specific surface area of about 10 to about 800 m²/g,and a specific pore volume of about 0.2 to about 3.0 cc/g. The at leastone spherically shaped microcomposite comprises a perfluorinatedion-exchange polymer containing pendant sulfonic and/or carboxylic acidgroups entrapped within and highly dispersed throughout a network ofinorganic oxide, wherein the weight percentage of the perfluorinatedion-exchange polymer in the microcomposite is from about 0.1 to about 90percent. The size of the pores in the microcomposite is about 0.5 nm toabout 75 nm. Preferably, the pore size is about 0.5 to about 50 nm, mostpreferably about 0.5 to about 30 nm.

In step (a) of the process of the present invention, a water-miscibleinorganic oxide network precursor system is combined with awater-miscible liquid composition comprising a perfluorinatedion-exchange polymer containing pendant sulfonic and/or carboxylic acidgroups, and an organic liquid to form a two phase liquid system.Although the sequence of combining the components of the two phaseliquid system is not critical, preferably the water-miscible componentsare contacted with each other first followed by contact with the organicliquid.

The water-miscible inorganic oxide network precursor system comprises aninorganic oxide network precursor, water and optionally a catalyst.

The “inorganic oxide” signifies metallic, semimetallic or otherinorganic oxide compounds, including, for example, alumina, silica,titania, germania, zirconia, alumino-silicates, zirconyl-silicates,chromic oxides, germanium oxides, copper oxides, molybdenum oxides,tantalum oxides, zinc oxides, yttrium oxides, vanadium oxides, and ironoxides. Alumina, silica, titania and zirconia are preferred, and silicais most preferred. The term “inorganic oxide network precursor” refersto an inorganic oxide precursor or an inorganic oxide initially used inthe present process to yield a network of inorganic oxide in theresultant at least one spherically shaped microcomposite. Most inorganicoxide network precursors will hydrolyze and condense into the network ofinorganic oxide during the course of the present process. Otherinorganic oxide network precursors exist initially as an inorganicoxide, such as colloidal silica.

In the case of silica, for example, a range of silicon alkoxides can behydrolyzed and condensed to form the network of inorganic oxide. Suchinorganic oxide network precursors as tetramethoxysilane,tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and anycompounds under the class of organic alkoxides which in the case ofsilicon is represented by Si(OR)₄, where R, which can be the same ordifferent, includes methyl, ethyl, n-propyl, iso-propyl, n-butyl,sec-butyl, iso-butyl, tert-butyl can be used. Also included as aninorganic network precursor is silicon tetrachloride. Further inorganicoxide network precursors comprise organically modified silica, forexample, CH₃Si(OCH₃)₃, PhSi(OCH₃)₃,where Ph is phenyl, and(CH₃)₂Si(OCH₃)₂. Other inorganic oxide network precursors include metalsilicates, for example, potassium silicate, sodium silicate and lithiumsilicate. As an alternative to using as is, the potassium, sodium orlithium ions of these metal silicates can be removed using a DOWEX®cation exchange resin (sold by Dow Chemical, Midland, Mich.), whichgenerates polysilicic acid which gels at slightly acid to basic pH. Theuse of LUDOX® colloidal silica (E. I. du Pont de Nemours and Company,Wilmington, Del.) and fumed silica (CAB-O-SIL® sold by Cabot Corporationof Boston, Mass.) which can be gelled by altering pH and adjusting theconcentration of the silicon species in solution will also yield anetwork of inorganic oxide in the spherically shaped microcomposite ofthe present invention. Preferred inorganic oxide network precursors forsilica are tetramethoxysilane, tetraethoxysilane and sodium silicate;and a preferred inorganic oxide network precursor for alumina isaluminum tri-secbutoxide Al(OC₄H₉)₃.

The amount of water used in the inorganic oxide network precursor systemof the present process is at least sufficient for the completehydrolysis and condensation of those inorganic oxide network precursorsthat are not already hydrolyzed and/or condensed. Preferably, an excessamount of water is used as compared with the stoichiometrically requiredamount. The amount of water required for hydrolysis depends on the rateof hydrolysis of each inorganic oxide network precursor used. Generally,hydrolysis takes place more rapidly with increasing amounts of water.Hydrolysis can begin upon contact of the inorganic oxide networkprecursor with the water.

The amount of water needed in the inorganic oxide network precursorsystem when inorganic oxides, such as colloidal silica, are used as theinorganic oxide network precursor is that which is sufficient to providea water-miscible system upon its contact with the inorganic oxidenetwork precursor.

Optionally, the water-miscible inorganic oxide precursor system mayfurther comprise a catalyst. Representative examples of suitablecatalysts are HCl, H₃PO₄, CH₃COOH, NH₃, NH₄OH, NaOH, KOH and NR¹ ₃,wherein R¹ represents an alkyl group which contains 1 to 6 carbon atoms.The catalyst can be added with stirring.

The temperature during formation of the water-miscible inorganic oxidenetwork precursor system can range from about 0° C. to about 100° C.Atmospheric pressure can be used.

Agitation, such as by stirring or ultrasonication, should be used, ifnecessary, to effect good contact of the inorganic oxide networkprecursor with the water and with the optional catalyst. Agitation maynot be required for the formation of every inorganic oxide networkprecursor system.

The water-miscible liquid composition comprising a perfluorinated ionexchange polymer (PFIEP) containing pendant sulfonic acid, carboxylicacid, or sulfonic acid and carboxylic acid groups used in the presentinvention are well known compounds. See, for example, Waller et al.,Chemtech, July 1987, pp. 438-441, and references therein, and U.S. Pat.No. 5,094,995, incorporated herein by reference. PFIEP containingpendant carboxylic groups have been described in U.S. Pat. No.3,506,635, which is also incorporated by reference herein. Polymersdiscussed by J. D. Weaver et al., in Catalysis Today, 14 (1992) 195-210,are also useful in the present invention. Polymers that are suitable foruse in the present invention have structures that include asubstantially fluorinated carbon chain that may have attached to it sidechains that are substantially fluorinated. In addition, these polymerscontain sulfonic acid groups or derivatives of sulfonic acid groups,carboxylic acid groups or derivatives of carboxylic acid groups and/ormixtures of these groups. For example, copolymers of a first fluorinatedvinyl monomer and a second fluorinated vinyl monomer having a pendantcation exchange group or a pendant cation exchange group precursor canbe used, e.g. sulfonyl fluoride groups (SO₂F) which can be subsequentlyhydrolyzed to sulfonic acid groups. Possible first monomers includetetrafluoroethylene (TFE), hexafluoropropylene, vinyl fluoride,vinylidine fluoride, trifluoroethylene, chlorotrifluoroethylene,perfluoro (alkyl vinyl ether), and mixtures thereof. Possible secondmonomers include a variety of fluorinated vinyl ethers with pendantcation exchange groups or precursor groups. Preferably, the polymercontains a sufficient number of acid groups to give an equivalent weightof from about 500 to 20,000, and most preferably from 800 to 2000.Representative of the perfluorinated polymers, for example, are thoseused in membranes, such as NAFION®, commercially available from E. I. duPont de Nemours and Company), and polymers, or derivatives of polymers,disclosed in U.S. Pat. Nos. 3,282,875; 4,329,435; 4,330,654; 4,358,545;4,417,969; 4,610,762; 4,433,082; and 5,094,995. More preferably thepolymer comprises a perfluorocarbon backbone and a pendant grouprepresented by the formula —OCF₂CF(CF₃)OCF₂CF₂SO₃X, wherein X is H, analkali metal or NH₄. Polymers of this type are disclosed in U.S. Pat.No. 3,282,875.

Typically, suitable perfluorinated polymers are derived from sulfonylgroup-containing polymers having a fluorinated hydrocarbon backbonechain to which are attached the functional groups or pendant side chainswhich in turn carry the functional groups. Fluorocarbosulfonic acidcatalysts polymers useful in preparing the spherically shapedmicrocomposites of the present invention have been made by Dow Chemicaland are described in Catalysis Today, 14 (1992) 195-210. Otherperfluorinated polymer sulfonic acid catalysts are described inSynthesis, G. I. Olah, P. S. Iyer, G. K. Surya Prakash, 513-531 (1986).

There are also several additional classes of polymer catalystsassociated with metal cation ion-exchange polymers and useful inpreparing the at least one spherically shaped microcomposite of thepresent invention. These comprise 1) a partially cation-exchangedpolymer, 2) a completely cation-exchanged polymer, and 3) acation-exchanged polymer where the metal cation is coordinated toanother ligand (see U.S. Pat. No. 4,414,409, and Waller, F. J. inPolymeric Reagents and Catalysts; Ford, W. T., Ed.; ACS Symposium Series308; American Chemical Society; Washington, D.C., 1986, Chapter 3).

Preferred PFIEP suitable for use in the present invention comprise thosecontaining sulfonic acid groups, such as a sulfonated PFIEP preparedfrom a NAFION® solution. More preferred is a PFIEP prepared from resinshaving an equivalent weight of about 800 to 2000 comprisingtetrafluoroethylene and perfluoro(3,6-dioxa-4-methyl-7-octenesulfonylfluoride).

PFIEP are used within the context of the present invention in a liquidcomposition form (also commonly called solutions) which can be preparedusing the process in U.S. Pat. No. 4,433,082 or Martin et al., Anal.Chem., Vol. 54, pp 1639-141(1982) incorporated by reference herein.Solvents and mixtures other than those in U.S. Pat. No. 4,433,082 andMartin et al. may also be effective in preparing the liquid compositionof PFIEP. The liquid composition of PFIEP can be used directly and maybe filtered through fine filters (e.g., 4-5.5 micrometers) to obtainclear, though perhaps slightly colored, solutions. The liquidcompositions of PFIEP obtained by these processes can be furthermodified by removing a portion of the water, alcohols and any volatileorganic by-products by distillation, e.g. to give a liquid compositioncontaining water only.

Commercially available liquid compositions of perfluorinatedion-exchange polymer can also be used in the preparation of the at leastone spherically shaped microcomposite of the present invention (e.g., a5 wt % solution of a perfluorinated ion-exchange powder in a mixture oflower aliphatic alcohols and water, Cat. No. 27,470-4, Aldrich ChemicalCompany, Inc., 940 West Saint Paul Avenue, Milwaukee, Wis. 53233).

Optionally, the liquid composition comprising PFIEP may further comprisean acid or base catalyst. The catalyst acts to allow network formationof the water-miscible inorganic oxide network precursor system viagelation to occur, and/or it increases the rate of gelation once in thepresence of the water-miscible inorganic oxide network precursor system.

Formation of the liquid composition comprising PFIEP can be made at atemperature ranging from about 0° C. to about 100° C. Atmosphericpressure can be used. Some agitation may be required to obtain goodcontact between the liquid composition of PFIEP and the catalyst thatcan optionally be added.

If the water-miscible inorganic oxide network precursor system and thewater-miscible liquid composition comprising PFIEP are first contactedtogether prior to their combination with the organic liquid, someagitation may be required to obtain good contact between thesecomponents.

The organic liquid combined with the water-miscible inorganic oxidenetwork precursor system and the water-miscible liquid compositioncomprising PFIEP in step (a) does not solubilize either thewater-miscible inorganic oxide network precursor system (which may behydrolyzed and/or condensed) or the water-miscible liquid composition ofPFIEP. The result of the combination of the organic liquid, thewater-miscible mixture inorganic oxide network precursor system andwater-miscible liquid composition comprising PFIEP is a two phase liquidsystem, one phase being the organic liquid and the other phasecomprising the water-miscible inorganic oxide network precursor systemand the water-miscible liquid composition comprising PFIEP. The amountof organic liquid used can be 10 to 2000%, preferably 25 to 1000% byweight, with reference to the total amount of inorganic oxide networkprecursor used. Assessment of the amount of organic liquid used alsodepends in particular on what particle size is being sought for eachspherically shaped microcomposite. Generally, less organic liquid isused for coarse particles (spheres with a larger diameter) and more isused for fine particles (spheres with a smaller diameter).

Suitable organic liquids are, e.g. hydrocarbons with 4 to about 40carbon atoms, such as long chain aliphatic compounds, aromatic compoundsor mixtures of aromatic compounds substituted with one or more alkylgroups, e.g. toluene or xylene isomers (separately or in a mixture);chlorinated or fluorinated hydrocarbons; linear or branched alcoholswith 6 to 18 carbon atoms; phenols; dialkyl ethers which can be linearor branched, symmetric or asymmetric; di- or tri-ethers (such asdimethyl ether); and ketones which can be symmetric or asymmetric andare predominantly immiscible with water. Preferably, the organic liquidis toluene or o-, m- or p-xylene, separately or as a mixture, ormesitylene, kerosene or cumene.

In step (b) of the present process, the two phase liquid system isagitated sufficiently to sustain a dispersion of the water-misciblephase in the shape of spheres in the organic phase. The temperature atwhich dispersion of the second water-miscible mixture in the organicliquid is performed and spherical solids are formed from this dispersedphase, generally ranges from about 0° C. to about 100° C.

In step (c) of the present process, the water-miscible inorganic oxidenetwork precursor system is allowed to form a network of inorganicoxide. Network formation is accomplished via gelation of thewater-miscible inorganic oxide network precursor system which may insome instances self-initiate due to the presence of the water. In otherinstances, network formation is allowed by initiating gelation, whichcan be achieved in a number of ways depending on the PFIEP and theinorganic oxide network precursor selected. Initiation of gelation andthe rate of gelation are dependent on a number of factors, such as theamount of water present, pH and the nature of any acid or base used,temperature, pressure, and concentration of the inorganic oxide networkprecursor. The time required for the network formation can thus varywidely depending on these factors from practically instantaneous toseveral days.

As discussed above, a larger amount of water can increase the rate ofhydrolysis and thus the eventual rate of gelation. However, more watercan slow down the rate of gelation when colloidal silica is used becauseof the dilution factor. A higher concentration of the inorganic oxidenetwork precursor can result in a faster rate of gelation.

Gelation can be carried out over a wide range of acidity and basicity.Network formation can be formed by acid catalyzed gelation (see Sol-GelScience, Brinker, C. J. and Scherer, G. W., Academic Press, 1990).Although gels can be formed using acid only, the rate of gelation isusually slower when acids are used. Representative examples of suitablecatalysts are HCl, H₃PO₄, CH₃COOH, NH₃, NH₄OH, NaOH, KOH and NR¹ ₃,wherein R¹ represents an alkyl group which contains 1 to 6 carbon atoms.Preferably, a suitable base, such as sodium hydroxide, lithiumhydroxide, ammonia, ammonium hydroxide, and organic amines, such aspyridine, are used. The pH adjustment using either acid or base can beachieved in a number of ways and is also dependent on the concentrationof acid or base employed. In order to allow network formation to occur,the acid or base can be contacted with either the water-miscibleinorganic oxide network precursor system or with the water-miscibleliquid composition comprising PFIEP prior to their combination with theorganic liquid, or the acid or base can be added to the two-phase liquidsystem. Some hydrolysis and condensation may occur prior to theformation of the two phase system. However, network formation should beavoided until the three primary components, the water-miscible inorganicoxide network precursor system, the water-miscible liquid compositioncomprising PFIEP and the organic liquid, of the two phase system arecombined and agitated. Thus, preferably, any needed catalyst is addedafter formation of the two-phase system to allow network formation tooccur.

Gelation can be carried out at virtually any temperature at which thewater-miscible phase is initially in liquid form. The reaction istypically carried out at room temperature. Raising the temperature canincrease the rate of gelation.

Gelling may be initiated at atmospheric pressure or at an excesspressure which corresponds to the sum of the partial pressures of thecomponents of the reaction mixture at the particular temperature beingapplied. The use of atmospheric pressure is preferred.

After formation, the at least one spherically shaped microcomposite, inthe presence or absence of the organic liquid, may optionally be allowedto stand for a period of time. This is referred to as aging. Aging ofthe wet spherically shaped microcomposite for a few hours to about two(2) days at about room temperature to about 200° C., preferably about75° C., leads to an increase in pore size and pore volume. This effectis characteristic of silica type gels, where the aging effect gives riseto an increasingly crosslinked network which upon drying is moreresistant to shrinkage and thus a higher pore size and higher porevolume results (see, for example, the text Sol-Gel Science, Brinker, C.J. and Scherer, G. W., Academic Press, 1990, pp.518-523).

In step (d), the solid, at least one spherically shaped porousmicrocomposite formed is recovered from the organic liquid after asufficient reaction time, at a temperature ranging from room temperatureto about 250° C. A sufficient reaction time is the time needed for thesphere to harden sufficiently to maintain its shape when recovered.Recovery of the moist microcomposite sphere from the organic liquid canbe accomplished by decanting, filtering or centrifuging.

The spheres can be optionally purified by extraction using azeotropicdistillation, i.e. removing the water from the spherically shapedmicrocomposite and replacing it with an organic solvent, such as analcohol. This distilled microcomposite may then be further treatedhydrothermally. Azeotropic distillation may take place prior to or afterrecovery of the spherically shaped microcoposite.

After recovery and optional aging, the spherically shapedmicrocomposites can be optionally dried at a temperature ranging fromroom temperature to about 250° C., optionally under a protective gas orunder vacuum, for a time sufficient to further harden and stabilize thespherically shaped microcomposites. Drying can take place from about 1hour to about one week.

Preferably, following removal of the organic liquid, the present processfurther comprises reacidification, washing, filtering or a combinationthereof, of the spherically shaped microcomposite. Reacidification,washing, filtering or a combination thereof, may be repeated a number oftimes. Reacidification of the spherically shaped microcompositeconverts, for example, the sodium salt of the perfluorosulfonic acidinto the acidic, active form. Suitable acids used for reacidificationcomprise HCl, H₂SO₄ and nitric acid. Washing can be done with deionizedwater, and the filtering removes excess acid Reacidification, washing,filtering, or a combination thereof can take place at a temperatureranging from room temperature to about 100° C. at atmospheric pressure,and for a time ranging from about one hour to about 24 hours.

A number of reaction variables, for example pH, temperature, aging,method of drying and drying time, have been found to affect the poresize and pore size distribution of the spherically shapedmicrocomposite. Both higher pH and longer aging of the sphericallyshaped microcomposite (before solvent removal) lead to larger final poresize in dried spherically shaped microcomposites.

The porous nature of the spherically shaped microcomposite can bereadily demonstrated, for example, by solvent absorption. Thespherically shaped microcomposite can be observed to emit bubbles whichare evolved due to the displacement of the air from within the porousnetwork.

It is believed that the spherically shaped microcomposites of thepresent invention comprise a continuous network of inorganic oxidehaving connected porous channels which entraps a highly dispersed PFIEPwithin and throughout the network. The distribution of the PFIEPentrapped within and throughout the network of inorganic oxide is on avery fine sub-micron scale. The distribution can be investigated usingelectron microscopy, with energy dispersive X-ray analysis, whichprovides for the analysis of the elements Si and O (when using silica,for example) and C and F from the PFIEP. The distribution of PFIEPwithin a spherically shaped microcomposite of the present invention isvery uniform.

The spherically shaped microcomposites of the present invention areuseful as ion exchange resins, and as catalysts, for example, foralkylating aliphatic or aromatic hydrocarbons, such as the alkylation ofnaphthalene with propylene; for decomposing organic hydroperoxides, suchas cumene hydroperoxide; for sulfonating or nitrating organic compounds;and for oxyalkylating hydroxylic compounds. Other catalytic applicationsfor the spherically shaped microcomposites of the present inventioncomprise hydrocarbon isomerization and polymerization, such as theisomerization of 1 -butene to 2-butenes; carbonylation and carboxylationreactions; hydrolysis and condensation reactions; esterifications andetherifications; hydrations and oxidations; oligomerizations; aromaticacylation; aromatic benzylation; and isomerization and metathesisreactions.

The spherically shaped microcomposite can be used as a catalyst in theisomerization of an olefin. Olefin isomerization is useful in convertingcompounds into isomers more useful for particular applications. Olefinswith the double bond at a terminal end tend to be more reactive and areeasy to oxidize which can cause problems with storage. Therefore, ashift to a more stable olefin form can be desirable.

Olefin isomerization processes can be directed towards either skeletalisomerization, double bond isomerization or geometric isomerization. Thespherically shaped microcomposite of the present invention can be usedas a catalyst for double bond isomerization and some geometricisomerization. Skeletal isomerization is provided to a limited degree athigher temperatures utilizing the spherically shaped microcomposite ofthe present invention.

The spherically shaped microcomposite can be used as a catalyst witholefins such as C₄ to C₄₀ hydrocarbons having at least one double bond,the double bond(s) being located at a terminal end, an internal positionor at both a terminal and internal position. Most preferred olefins have4 to 20 carbon atoms. The olefin can be straight-chained (normal) orbranched and may be a primary or secondary olefin and thus substitutedwith one or more groups that do not interfere with the isomerizationreaction. Such substituted groups that do not interfere with theisomerization reaction could include alkyl, aryl, halide, alkoxy,esters, ethers, or thioethers. Groups that may interfere with theprocess would be alcohols, carboxylic acids, amines, aldehydes andketones.

The spherically shaped microcomposite is contacted with the olefin in afixed-bed system, a moving-bed system, a fluidized-bed system, or in abatch-type operation. This contacting can be in the liquid phase, amixed vapor-liquid phase, or a vapor phase, in the absence of hydrogenor in the presence of hydrogen in a molar ratio of hydrogen to olefin offrom about 0.01 to about 10. Inert diluents such as helium, nitrogen,argon, methane, ethane and the like can be present either in associationwith hydrogen or in the absence of hydrogen.

Isomerization conditions using the present spherically shapedmicrocomposite comprise reaction temperatures generally in the range ofabout 0° C. to about 300° C., preferably from about 24° C. to about 250°C. Pressure can range from ambient for gas phase or a pressuresufficient to keep reaction in the liquid phase. Reactor operatingpressures usually will range from about one atmosphere to about 100atmospheres, preferably from about one atmosphere to about 50atmospheres. The amount of catalyst in the reactor will provide anoverall weight hourly space velocity (WHSV) of from about 0.1 to 100hr⁻¹, preferably from about 0.1 to 10 hr⁻¹; most preferably 0.1 to 2hr⁻¹.

Long contact time during olefin isomerization can create undesirableby-products, such as oligomers. Short contact times ranging from about0.01 hr to about 10 hrs; preferably 0.1 hr to about 5 hrs can be usedwith the present spherically shaped microcomposite. Contact time may bereduced at higher temperatures.

Any product recovery scheme known in the art can be used to isolate theresultant olefins. Typically, the reactor effluent will be condensed andthe hydrogen and inerts removed therefrom by flash separation. Thecondensed liquid product then is fractionated to remove light materialsfrom the liquid product. The selected isomers may be separated from theliquid product by adsorption, fractionated, or extraction.

EXAMPLES

NAFION® solutions can be purchased from Aldrich Chemical Co., Milwaukee,Wis., or PFIEP solutions generally can be prepared using the procedureof U.S. Pat. No. 5,094,995 and U.S. Pat. No. 4,433,082. The NAFION®PFIEP solution referred to in the examples below is, unless otherwisenoted, NAFION® NR005, a NAFION® solution available from DuPontFluoroproducts, Fayetteville, N.C., and also known as NAFION® SE-5110,and is prepared from resin which is approximately 6.3 (TFE) moleculesfor every perfluoro (3,6-dioxa-4-methyl-7-octene sulfonyl fluoride)molecule (CF₂═CF—O—[CF₂CF(CF₃)]—O—CF₂CF₂—SO₂F (PSEPVE)) and has anequivalent weight of approximately 1070. NAFION® NR50 catalyst, the sameresin used to prepared the NR005 (SE-5110) solution is available inpellet form from E. I. du Pont de Nemours and Company, Wilmington, Del.(distributed by Aldrich Chemical Company). AMBERLYST 15® sulfonatedresin is a registered trademark of Rohm and Haas, Philadelphia, Pa. andis sold commercially by Rohm and Haas.

Example 1

To 40 mls of Si(OCH₃)₄ was added 6 g of distilled water and 0.6 g of0.04M HCl. The mixture was stirred for one hour. 60 ml of a 5 wt %NAFION® solution (the PFIEP) was added to the silicon containingmixture. The mixture was agitated using a twin blade impeller to ensuregood mixing. 75 ml of mesitylene was then added and the mixture wasstirred. To the rapidly stirred solution 30 ml of 0.4M NaOH was addedand the mixture was stirred for a further hour. The product spheres werefiltered and dried at 140° C. in vacuum for 2-3 hours. The spheres werewashed and reacidified with 3.5M HCl, by covering with about 250 ml ofacid and leaving for 1 hour. The spheres were washed with water and theprocess of reacidification and washing was repeated a total of fourtimes. Finally, the product spheres were placed in about 100 ml of 25 wt% nitric acid and left at 75° C. overnight, followed by filtering andwashing with distilled water. The yield was about 18 g. Each sphericalparticle obtained was in the range of about 0.1 to 1.0 mm in size. Thecontent of PFIEP for each spherical particle was about 13 wt % measuredusing thermogravimetric analysis (TGA), where the PFIEP was decomposedand removed upon heating to between 400-500° C.

The surface area of a spherical particle was measured to be 316 m² perg, with a pore volume of 0.5 cc per g, and a pore diameter of 6 nm.

The distribution of the PFIEP within the sphere was very uniform. Thiswas determined by examining a particle which had been placed in epoxy.The particle was polished to show a polished cross section, where theinterior of the particle was examined. Energy dispersive X-ray analysiswas used to analyze the particle. Elemental analysis showed the presenceof Si, O, F and C from the silica network and the PFIEP respectively.The distribution of the PFIEP and silica was examined using a spot modewhich analyzed an area of about 100 nm. Larger areas were also examined.The ratio of F and Si was approximately the same in all areas of theparticle showing the uniformity.

Example 2

To 40 mls of Si(OCH₃)₄ was added 6 g of distilled water and 0.6 g of0.04M HCl. The mixture was stirred for one hour. 60 ml of a 5 wt %NAFION® solution (the PFIEP) was added to the silicon containingmixture. The mixture was agitated using a twin blade impeller to ensuregood mixing. 75 ml of mesitylene was then added and the mixture wasstirred. To the rapidly stirred solution 30 ml of 0.4M NaOH was addedand the mixture was stirred for a further hour. The mixture, includingall of the mesitylene solvent, was placed in ajar. The jar was sealedand placed in an oven at 75° C. to age overnight. The product sphereswere then filtered and dried at 140° C. in vacuum for 2-3 hours. Thespheres were washed and reacidified with 3.5 M HCl, by covering withabout 250 ml of acid and leaving for 1 hour. The spheres were washedwith water and the process of reacidification and washing was repeated atotal of four times. Finally, the product spheres were placed in about100 ml of 25 wt % nitric acid and left at 75° C. overnight, followed byfiltering and washing with distilled water. The yield was about 18 g.The content of PFIEP of each spherical particle was about 13 wt %measured using TGA. Each spherical particle obtained was in the range ofabout 0.1 to 1.0 mm in size. The content of PFIEP in each sphericalparticle was about 13 wt % measured using TGA. The surface area wasmeasured to be 317 m² per g, with a pore volume of 0.68 cc per g, and apore diameter of 8.4 nm.

Example 3

To 20 mls of Si(OCH₃)₄ was added 3 g of distilled water and 0.3 g of0.04M HCl. The mixture was stirred for one hour. The mixture wasagitated using a twin blade impeller to ensure good mixing. 70 ml ofmesitylene was then added and the mixture was stirred. To 30 ml of a 5wt % “NAFION®” solution (the PFIEP), 15 ml of 0.4 M NaOH was added overabout 30 seconds. This PFIEP containing mixture was added to the siliconcontaining mixture. The resulting mixture was stirred for 1 hour. Theproduct spheres were filtered and dried at 140° C. in vacuum for 2-3hours. The solid spheres were washed with 3.5M HCl by covering withabout 200 ml of acid and leaving for 1 hour. The spheres were washedwith water and the process of reacidification and washing was repeated atotal of four times. Finally, the product spheres were placed in about100 ml of 25 wt % nitric acid and left at 75° C. overnight, followed byfiltering and washing with distilled water. The yield was about 9 g.Each spherical particle obtained was in the range of about 0.1 to 1.0 mmin size. The content of PFIEP in each spherical particle was about 14 wt% measured using TGA.

Example 4

To 20 mls of Si(OCH₃)₄ was added 3 g of distilled water and 0.3 g of0.04M HCl. The mixture was stirred for one hour. 30 ml of a 5 wt %NAFION® solution (the PFIEP) was added to the silicon containingmixture. The mixture was agitated using a twin blade impeller to ensuregood mixing. 75 ml of cumene was then added and the mixture was stirred.To the rapidly stirred mixture, 15 ml of 0.4M NaOH was added and themixture was stirred for a further hour. The product spheres werefiltered and dried at 140° C. in vacuum for 2-3 hours. The solid sphereswere washed with 3.5 M HCl, by covering with about 200 ml of acid andleaving for 1 hour. The spheres were washed with water and the processof reacidification and washing was repeated a total of four times.Finally, the product spheres were placed in about 100 ml of 25 wt %nitric acid and left at 75° C. overnight, followed by filtering andwashing with distilled water. The yield was about 9 g. Each sphericalparticle obtained was in the range of about 0.1 to 1.0 mm in size. Thecontent of PFIEP of each spherical particle was about 12.5 wt % measuredusing TGA.

Example 5

To 40 mls of Si(OCH₃)₄ was added 6 g of distilled water and 0.6 g of0.04M HCl. The mixture was stirred for one hour. 60 ml of a 5 wt %NAFION® solution (the PFIEP) was added to the silicon containingmixture. The mixture was agitated using a twin blade impeller to ensuregood mixing. 150 ml of white kerosene was then added and the mixture wasstirred. To the rapidly stirred mixture, 30 ml of 0.4M NaOH was addedand the resulting mixture was stirred for a further hour. The productspheres were filtered and dried at 140° C. in vacuum for 2-3 hours. Thesolid spheres were washed with 3.5M HCl by covering with about 250 ml ofacid and leaving for 1 hour. The spheres were washed with water and theprocess of reacidification and washing was repeated a total of fourtimes. Finally, the spheres were placed in about 100 ml of 25 wt %nitric acid and left at 75° C. overnight, followed by filtering andwashing with distilled water. The yield was about 12 g. Each sphericalparticle obtained was in the range of about 0.1 to 1.0 mm in size. Thecontent of PFIEP in each spherical particle was about 13 wt % measuredusing TGA.

Example 6

To 208 g of Si(OCH₂CH₃)₄ (TEOS) was added 54 g of distilled water and 1g of 0.04M HCl and the mixture was stirred for 40 mins. This TEOSsolution was used in the following preparations.

(i) 55 mls of the above mixture was added to 60 ml of a 5 wt % NAFION®solution (the PFIEP). The mixture was agitated using a twin bladeimpeller to ensure good mixing at a setting of about 30. 200 ml ofKerosene was then added and the mixture was stirred. After about 30seconds, 40 ml of 0.4M NaOH was added to the rapidly stirred mixture,and the mixture was stirred for a further 15 mins. The product sphereswere filtered and dried at 100° C. in a nitrogen flow overnight. Thesolid spheres were washed with 3.5M HCl by covering with about 200 ml ofacid and leaving for about 1 hour. The spheres were washed with waterand the process of reacidification and washing was repeated a total offour times. Finally, the spheres were placed in about 100 ml of 25 wt %nitric acid and left at 75° C. overnight, followed by filtering andwashing with distilled water. Each spherical particle obtained was inthe range of about 0.1 to 0.3 mm in size. The yield was about 9 g. Thecontent of PFIEP in each spherical particle was about 13 wt % measuredusing TGA.

(ii) 55 mls of the TEOS mixture was added to 60 ml of a 5 wt % NAFION®solution (the PFIEP). The mixture was agitated using a twin bladeimpeller to ensure good mixing at a setting of about 15. 200 ml ofkerosene was then added and the mixture was stirred. After about 30seconds, 40 ml of 0.4M NaOH was added to the rapidly stirred mixture,and the mixture was stirred for a further 15 mins. The product sphereswere filtered and dried at 100° C. in a nitrogen flow overnight. Thesolid spheres were washed with 3.5 M HCl by covering with about 200 mlof acid and leaving for about 1 hour. The spheres were washed with waterand the process of reacidification and washing was repeated a total offour times. Finally the spheres were placed in about 100 ml of 25 wt %nitric acid and left at 75° C. overnight, followed by filtering andwashing with distilled water. The yield was about 9 g. Each sphericalparticle had a larger average particle diameter than in (i) above, i.e.,in the range of about 0.1 to 1.0 mm in size. The content of PFIEP ineach spherical particle was about 13 wt % measured using TGA.

Example 7 Alkylation of Naphthalene with Propylene over Spherical ShapedMicrocomposite

The title reaction was carried out with spherical 13 wt % PFIEP/silicamicrocomposite of the present invention used as a catalyst and comparedwith NAFION® catalyst (NR-50) and AMBERLYST-15®. In a 250 ml threeneck-flask was added 75 g decalin as solvent, 6.4 g naphthalene (0.05M)and 2.0 g of the solid acid catalyst. Once the reaction temperature of100° C. was reached, the alkylation reaction as started by bubblingpropylene through the naphthalene solution. Liquid sample was taken forgas chromatography (GC) analysis. At 100° C., the naphthalene topropylene molar ratio was determined to be 2.2/1.0 determined by GC. Thespherical 13 wt % NAFION® PFIEP/silica microcomposite was the mostactive catalyst. The results are listed in Table 1. Table 1. Naphthaleneconversion (mol %) after 1 hr at 100° C. for the alkylation ofnaphthalene by propylene over 2 g of solid acid catalyst

TABLE 1 Naphthalene conversion (mol %) after 1 hr at 100° C. for thealkylation of naphthalene by propylene over 2 g of solid acid catalystCatalyst Conv. % Spherical Microcomposite 42.2 AMBERLYST-15 ® 10.7NAFION ®  6.4

Example 8 1-Butene Isomerization to 2-Butenes

1-Butene isomerization to cis-2-butene, trans-2-butene and isobutene wascarried out at 22, 50 and 75° C. and ambient pressure with a ½″stainless steel reactor and 5.0 g spherical 13 wt % PFIEP/silicamicrocomposites of the present invention as a catalyst. Prior to thereaction, the spherically shaped microcomposites were dried in a vacuumoven at 150° C. for overnight. The reaction mixture was analyzed by anon-line GC equipped with a 25 m Plot column coated with Al₂O₃/KCl(Chrompack Inc., Raritan, N.J.). At room temperature (22° C.), asignificant amount of 1-butene was converted to 2-butenes at weighthourly space velocity (WHSV) of 2.5 hr⁻¹. n-Butene distribution reachednear thermodynamic equilibrium level at 75° C., which is 5.3%, 67.5%,and 27.2% for 1-butene, trans-2-butene, and cis-2-butene, respectively.Isobutene and butene oligomers were produced only in trace amounts underthese conditions.

Table 2. Product distribution for the 1-butene isomerization over 5.0 gspherical 13 wt % PFIEP/silica microcomposite under ambient pressurewith flow rates of He=110 ml/min and 1-butene=90 ml/min, WHSV of1-butene=2.5 hr⁻¹

TABLE 2 Product distribution for the 1-butene isomerization over 5.0 gspherical 13 wt % PFIEP/silica microcomposite under ambient pressurewith flow rates of He = 110 ml/min and 1-butene = 90 ml/min, WHSV of1-butene = 2.5 hr⁻¹ Temperature (° C.) % Butenes 22 50 75 1-butene 87.3 25.8  6.7 trans-2-butene 5.2 44.8 65.9 cis-2-butene 7.5 29.4 27.4isobutene — — —

Example 9 Alkylation of Toluene with n-Heptene

Both toluene and n-heptene were dried for 24 hours over a 3 A molecularsieve before use. In a round bottom flask was added 15.6 g of tolueneand 8.4 g of n-heptene, and a fluoropolymer coated magnetic stirrer wasadded. A reflux condenser was attached to the flask and a slow stream ofnitrogen passed over the top of the reflux condenser to minimizemoisture. The flask and contents were heated to 100° C. A sample of 1 gof 13 wt % PFIEP/silica spherically shaped microcomposite was dried invacuum at 150° C. for 15 hours. The dried spherically shapedmicrocomposite was added to the toluene/n-heptene mixture, stirred andleft to react for two hours. After two hours a sample was removed andthe conversion of n-heptene was measured using gas chromatography (GC).In the GC analysis dodecane was used as a standard. The conversion ofn-heptene was measured to be 99%, leaving only 1% of the n-hepteneunreacted.

Example 10 Benzylation of Benzene and p-Xylene with Substituted BenzylAlcohol

The benzylation reaction was carried out by heating a stirred mixture ofp-methylbenzyl alcohol and benzene or p-xylene, and the solid acidcatalyst at a temperature of 80° C. for the benzene mixture and at atemperature of 100° C. for the p-xylene mixture. Solid acid catalystsemployed for the benzylation reaction include 13 wt % PFIEP/silicacomposite in spherical form, NAFION® catalyst (NR-50), andAMBERLYST-15®. For one run, the composition of the mixture wascatalyst/alcohol/benzene=2.0/7.5/75 g and for another run thecomposition of the mixture was catalyst/alcohol/p-xylene=0.5/7.5/75 g.The reaction was carried out with nitrogen flow (at 200 cc/min) orwithout nitrogen. Liquid samples were taken at certain time intervalsand analyzed by a GC equipped with Flame Ionization Detectors (FID).Reaction rate and rate constants were determined.

The acid catalyzed reactions produced the desirable benzylation product,substituted diphenylmethane (I), as well as di-p-methylbenzyl ether(II), the dehydration product from the benzyl alcohol.

The di-p-methylbenzyl ether can be used as the benzylation agent aswell. Table 3 lists the product yields (%) after 1 hour of reactiontime. Data inside the parentheses are obtained without nitrogen flow.Since flowing nitrogen has a pronounced positive effect on thebenzylation reaction, standard runs are all carried out with nitrogenflow.

Table 3. Product yields (%) for the solid acid catalyzed benzylation ofbenzene and p-xylene with p-methylbenzyl alcohol after 1 hour(catalyst/alcohol/benzene 2.0/7.5/75 g orcatalyst/alcohol/p-xylene=0.5/7.5/75 g).

TABLE 3 Product yields (%) for the solid acid catalyzed benzylation ofbenzene and p-xylene with p-methylbenzyl alcohol after 1 hour(catalyst/alcohol/benzene = 2.0/7.5/75 g or catalyst/alcohol/p-xylene =0.5/7.5/75 g). in Benzene in p-Xylene Catalyst I II I II Spherical 81.618.4 100.00 0.0 Microcomposite NAFION ® 71.2(50.2) 10.3(33.6) 66.0(29.6)16.3(13.1) AMBERLYST-15 ® 2.2(1.8) 1.0(1.2) 0.5(0.9) 0.7(1.6)

What is claimed is:
 1. A method for the benzylation of an aromaticcompound, comprising: contacting the aromatic compound with asubstituted benzyl alcohol in the presence of a spherically shapedporous microcomposite catalyst comprising a perfluorinated ion-exchangepolymer containing pendant sulfonic and/or carboxylic acid groupsentrapped within and highly dispersed throughout a network of inorganicoxide, wherein the weight percentage of the perfluorinated ion-exchangepolymer in the microcomposite is from about 0.1 to about 90 percent, andwherein the size of the pose s in the microcomposite is about 0.5 nm toabout 75 nm.
 2. The method of claim 1 wherein the aromatic compound isbenzene or p-xylene and the substituted benzyl alcohol is p-methylbenzvlalcohol.